Fluid pressure brake



May 31,r 1932.

M. HANcocK 1,860,413

FLUID PRESSURE BRAKE Filed Feb. 2l, 1929 INVENTOR MILTON L .HANCOCIr ATTORNEY Patented gMayv 31,` 1932 PATEN OFFH f y MILToN L. nancooii, on EAST Meiinnsroar, PENNSYLVANIA, AssIeNon 'ro 'riin'WEsTf rLUii) :Pnnssnan BRAKE Application led l'ebruaryV 21, 1929. Serial No. `341,596.

This invention relates toy fluid pressure brakes and more Yparticularly to a variable load brake. Y 'n l It has heretofore been proposed to provide a'variable load brake equipment for varying rthe braking power ona car in accordance with the load carried, in which equipment separate limiting valve means were employed for reg# ulating the braking power for both service and Ven'iergency applications.

for regulating the braking power on a car in both service and emergency applications and means :fior changing the adjustment ot said limiting valve to increase the braking power on a car when an emergency application of the brakesis effected.

In the accompanying drawings; Figure 1 is a diagrammatic view, partly in section, of a -fluid pressure brake system containing a varif able load mechanism embodying my inven@ tion; F ig. 2 isa sectional view of the brake.

valve device,fshowing the rotary valvey in Y service position; Fig. 3 isa sectional view of the brake valve device, showing the rotary valve in emergency position; Fig.A 4 is a sectional view of a portion of the variable load apparatus shown in Fig. 1 and illustrating a modified vforni of my invention; and Fig.` 5 is a sectional view of a portion of the variable load apparatus shown vin Fig.; `1 .andfil-l lustrating another modified formfof my-'ini vention.y .y L Q f f f yAs shown inV F ig, 1 of the drawings, the fluid pressure'brake system comprisesl a brake valve device 1, a-variable load mechanism2, a brake cylinder 3 and a'main reservoir 4.

The brake valve device 1l comprises a casing havinga chamber 5 containinga rotary valve 6. i VA handle7 is adapted to turn said vrotary val-ve through a key 8 disposed ina vertical bore in tliecasing and engaging at thelower endsaid rotary valve. 's

Thewvariable load mechanism comprises a brake cylinder pressure limitingvalve device 9, a brake cylinder siipply valve ydevice 10, a locking mechanism 11, a strut cylinder 12 and an emergency-adjusting device 13.

' The Vbralnicylinder pressure limiting valve device 9 comprises aiexible diaphragm 14, j

which is subject on one sideto the pressure of iiuid in the brake cylinder 3 asy supplied through passage 15, chamber 16 and passage '17, and on the opposite side 'to the pressure Y of a coil spring 18 acting on an abutment 96, which is maintained in engagement with said diaphragm Aby said spring. `A plunger y 19engaging tlie'freel end of the spring 18 is lThe principalfyobject of. this invention is toy Vprovide an improved variable vload brake equipment vemploying only one limiting valve provided in-order to vary the pressure eX- erted by said spring. The flexible diaphragm 14 is adapted to operate a valve 20 which controls the operation of the brake cylinder supply valve device anda spring 21'is provided to urge thevalve 20 to its seat.

The brake cylinder supply valve deviceflO comprises avalve piston 22, subject on one f side t0 the, pressurel of'a spring 23 and on' Y,

the innerfseated areawof the opposite side, to the pressure in chamber 16 as' supplied from theibrakecylinder '3, the outer seated. area kof said valve piston being subjectV to the pressure in a chamberf24,^which is con-v A l nected through 'passage and pipe 25 tothe service port 26 in the brakevalve device Pivotally mountedon the cap of the strut cylinder 12 is a member having crank arms oncrank arml 27V is adapted toengage one 27,28 and 29.v A roller 30 pivotally mounted lso 'end of the plunger 19 for edecting kan ad'- lThevalve device 38coinprises avalvepis-k n z95 j 'a spring 40andfonthe inner seated area off 1 ton 39 subject on one side to the pressure of thev opposite side to the pressure of fluid in passage and pipe 41 which is connected to the usual doorfopening` pipe (not shown).

. lo N Secured to the seating yface of the valve pis'- throughlpassage 37 from ton 39 is a stem member 42, which engages a. ball check valve 43 and is adapted, when said valve piston is held seated by the spring 40, to hold the ball check valve 43 from its seat.

The strut cylinder 12 is carried by the .locking mechanism casting and contains a piston 44, the stem of which is pivotally connected to a. lever 45. The lever 45 is pivotally connected at one end to a rod 46, which in turn is pivotally connected to the crank arm 28. The other end of lever 45 is pivotally connected to a member (not shown) mounted upon the car body, said member being adapted to engage another member on the car truck for adjusting the variable load mechanism in a manner disclosed in Letters kPatent No. 1,572,196 granted to Clyde C. Farmer on February 9, 1926.

The emergency adjusting device 13 is preferably mounted on a bracket 60 secured to the kcasing of t-he limiting valve device 9 and comprises a piston 47 subject on one side to the pressure of a spring 48 and subject on the o posite side to the pressure of fluid in cham er 49, which is supplied thereto through pipe 50 from the brake valve device 1,in all positions of said brake valve device except emergency position. In emergency position pipe 5() is connected to the atmosphere, as shown in Fig. 3 of the draw- 111gk The piston 47 has an upwardly extending hollow stem 51 mounted in a suitable bore vin they casing, and loosely contained in the piston stem 51 is a push rod 52. The upper end of said push rod ispivotally connected rto a lever. 53, which lever is pivotally mounted on a fulcrum pin 54 in the casing. One end of the lever 53 extends through an opening 55 in the casing of the limiting valve device and through an elongated slot 56 in the plunger 19, and within said slot is adapted to engage the` end of a stem 98 secured to the abutment 96. The otherend of said lever is connected to one end of a tension spring 57, the other end of said spring being connected by an adjusting screw 59 to a bracket 58 mounted on the car body.

In o era-tion, fluid under pressure is supplied rom a main reservoir 4to the rotary valve chamber5 of the brake valve device 1 through pipe and passage 61. Vith the brake valve in running position, as shown in Fig. lof the drawing, fluid under pressure flows from the rotary valve chamber 5 through port 62 in the rotary valve 6 and passage and pipe 50 to piston chamber 49 of the emergency adjusting device 13 and acts on the piston 47.y The pistou 47 is thereby moved upwardly against the'pressul'e of spring 48 to the position shown in the drawing, in which piston 47 engages a stop 63. Upward movement of said piston causes the push rod 52 to rotate the lever 53 clockwise on the fulcrum 54, so that the right hand end of said lever does not engage the abutment stem 98, but instead is located in an intermediate position in the yslot 56 in the plunger 19.

Whenthe brake valve device is in release position, the brake cylinder 3 is connected to the atmosphere through pipe and passage 15, chamber 16, past the ball check valve 100,

chamber 24, passage and pipe 25, port 26v past the ball check valve 43 and through passage 64 to the strut cylinder 12. The fluid pressure thereby builds up in chamber 65, on the piston 44 and forces said piston outwardly against the pressure exerted by a spring 66. The pawl 34 being'held in engagement with teeth 33 of the ratchet bar 32 by the spring 36', the crank arms 29, 28 and 27 are held against movement, so that the pivot pin 67 acts as a fulcrum for the lever 45, so that outward movement of the strut piston 44 will rotate the lever 45 about the pivot 67 an amount varying with the load on the car, in the usual manner The spring 40 is of such resistance as to hold the valve piston 39 seated in the position shown in the drawings, until after the strut piston has moved outwardly as hereinbefore described, at which time the fluid pressure acting on the inner seated area on the upper face of said valve piston becomes sufhcient to shift said valve piston to its downward position, in which. the ball check valve 43 is permitted to seat and fluid under pressure then flows from passage 41, past the valve piston 39 and through passage 37 to the left hand side of pawl piston 35. The pawl piston 35 is thereby moved to the right against Vthepressure exerted by spring 36, so as to disengage the pawl 34 from teeth 33 of the ratchet bar 32.

If the car load is now increased, the lever 45 is rotated in a clockwise direction, which, throughV the rod 46, also rotates the crank arms 27, 28 and 29 in a clockwise direction.

vented from the chamber at the left hand side l veco 84 into engagement withfthe teeth 330i the,

`ratchet bar. 32, so'as to maintain the ratchet bar and the crank arms' 27 28 Aand 29` andy the limiting valve spring18 inthe newly ad,- justed position. After the pawl thus moves into engagementV with the teeth 33 of the ratchet bar 32, the valve piston 39is shifted to', its upper position by spring 40. The ball check'valve 43 is thereby unseated, which permits the fluid under pressure to be vented from thechamber at the left side of the strut pistonf 44.` Thev strut Vpiston ist-hen moved back to its normal position, as shown in the drawings, by the pressure exerted by spring 66. v e v Y It is evident that the apparatus will oper# ate in the manner hereinbefore described to increase or decrease the pressure of theliinitingfvalve spring18 in accordance with the load carried on the car. x

ln order to effect a service application of the brakes for stopping the carV attlie next loading place, the brake valve handle 7 is operatedv to turn the rotary valve 6 to the service position shown infFig. 2 of the drawings. l In service position lof the brake valve, fluid under pressure flows fromtherotaryvalve chamber 5, which is connected through passage andv pipe 61 to the main reservoir 47 through ports y 69 and 26, and pipe and passage 25 to chamber 24in the variable load device, wherein itacts on the exposed area of the valve piston 22.' Said valve piston is then unseated, permitting fluid to How to chamber 16, thence through passage and pipe 15 to the brake cylinder 8. Fluid from chamber 24 also flows through the restricted portA 71 to the spring side of valve piston 22 and escapes therefrom through passage 72,'past the unseated limiting valve 20, thence through passage 17, chamber 16 and passage and pipe 1,5 to the brake cylinder 3.

sure then quickly equalizes onthe opposite sides Vof, said valve piston through the restricted passage 71, so that the spring 23 will f seat said valve piston and prevent further flow of fluid to thebrakecylinder. f

In service position of the brakevalve device, the pressure of the fluid in the emergency jadjustingpiston chamber V49` is maintained,

due to the connection through pipe and pasySage 50 and port 62 in the rotary valve 6 to the chamber 5, so that the emergency adjust' ing device 13 remains inoperative.

In ordery to eiect an emergency application yof the brakes, the brake valve handle 7 is Vop-` erated to turn the rotary valve 6 to emergency position, as sliown inFig. 3 of the drawings.

ln emergency osition of the brake valve device, iuid under pressure flows through port in the rotary valve 7 and passage and pipe 25 to ythe variable load device 2 and from thence to the brake cylinder 3 in the same manner as in aservice application of the brakes.. y

in emergency device Al, the emergency adjusting piston chamber 49 is Yvented to the atmosphere through pipe and passage 56,'cavity 78 in the rotary valve 6 and an atmospheric passage 7 4. VThe piston 47 is then shifted downwardly `away from the push rod 52 by spring 48. rlhe pressure eXertedby the tension spring 57'then rotates the lever 53 ycounter-clockwise on'the fulcrum pin 54, causing' the right hand end of said lever to engage the abutment stem 98. v'The predetermined tension force of the spring 57 on the abutment 96 is thereby added to the pressure of the limiting position of the brake valvel tainedin a service application of the brakes Y f by anamount equal to the added force of spring 57. When the brake cylinder pressure does become sufficient, to overcome the combined forces of the springs 18 57, the diaphragm 14 is deflected downwardly, therebyl permittinglvalve20 and valve piston 22 to operate to cut offf'the flow of fluid under pressure to the brake cylinder in the same 'Y ymanner asin a` service application ofthe` brakes. v

lt lwill be obvious, that no matter what the adjustment of the limiting valve spring `18, the ypredeterniined force of spring 57 will always be added to the force of spring 18011 theabutment 98 so that the brake cylinder pressure obtained in an emergency application of thebrakes will always be a predetery mined degreev greater than the pressure obtained in a service application of thebrakes z and willva'ry infa'ccordance with the `load on the car, due to the variableadjustmentof spring118. f

The tension of the spring 57 may be changed, so as to obtain any desired degree of pressure increase in an emergency application of the brakes. In order to change the tension of said spring, the position of the ad-` justing nut 7 5 and lock nut 76 on the screw 59 may be varied to permit said screw to extend through the bracket only an amount sufficient to obtain the desired tension force in the spring 57 and then by means of said lock nut, such adjustment can be fixed.

In the equipment shown in Fig. 1, when effecting an emergency application of the brakes, the fluid under pressure from the emergency adjusting piston chamber 49 Ais vented through the brake valve device in the mannerhereinbefore described. On account of the volume of said chamber and the connecting pipe .50, a certain period of time elapses between the operation of the brake valve device 1 to emergency position and the resultant movement of the piston 47. Since in effecting an emergency application of the brakes, it is desirable to obtain the brake cylinder pressure as rapidly as possible, means may be provided as shown in Figs.v4 and 5 for hastening the operation of the emergency adjusting device 13, in the manner herein-V after described.

In Fig. 4 of the drawings, the means provided for hastening the rate of venting of fluid under pressure from the piston chamber 49 comprises a piston 80 in a chamber 81 and a slide valve 82 in a valve chamber 83, the chamber 83 being connected to the adjusting piston chamber 49 through an unrestricted passage 84. Y

The piston chamber 81 is connected to pipe from the brake valve device, and fluid under pressure supplied to said pipe from said brake valve device, when in release position, acts on the piston 80. The piston 8O is thereby shifted to the position shown in the drawings, in which fluid under pressure flows from chamber 81 through a feed groove 85 to valve chamber 83, thence through passage 84 to the adjustingr piston chamber 49. The fluid pressure in chamber 49 then shifts the piston 47 upwardly, thereby rotating the le ver 53 clockwise in the same manner as hereinbefore described.

When an emergency application of the brakes is effected by movement of the brake valve device to emergency position, fluid under pressure is quickly vented from the piston chamber 81 and pipe 5() through the brake valve device. The flow area of the feed groove 85 is restricted, so that the pressure in the piston chamber 81 drops more rapidly than the pressure in the Vvalve chamber 83. The piston 85 is thereby shifted downwardly by the pressure in chamber 83 and in its downward position, port 86 in therslide valve registerscwith an atmospheric passage 87, thereby effecting an unrestricted connection from the valve chamber 83 and adjusting piston chamber 49 to the atmosphere. The fluid under pressure is thus quickly vented from the piston chamber 49, permitting the emergency adjusting device to operate in the same manner as hereinbefore described to increase the brake cylinder pressure in emergency.

The mechanism in Fig. 4 operates more rapidly than that shown in Fig. 1, since only the fluid under pressure from the small pistonr chamber 81 and pipe 59 is vented through the brake valve device. The piston 85 therefore operates sooner after movement of the brake valve device to emergency position than does the emergency adjusting piston shown in Fig. 1. After the piston 85 and slide valve 82 move, the emergency adjusting piston 47 may move almost instantly on account of the large atmospheric opening from the chamber 49. y

The modified form of my invention shown in Fig. 5 is similar to the form shown in Fig. 4 and comprises a valve piston 88 contained in a chamber 89 and subject at one side to kthe pressure. of a spring 90 for urging the valve piston to the left into engagement with aseat ring 91. In operation, when the brake valve device is in release or service' position, fluid under pressure is supplied through pipe 50 to the inner seated area of the valve piston 88 when seated against the seat ring 91 by the spring 90. When the fluid pressure thus acting on said valve piston becomes sufficient to overcome the pressure exerted by spring 99, the valve piston is shifted to the position shown in the drawings, in which communication is established from pipe 50, through chamber 89, thence through a restricted passage 92 and passage 93 to the adjusting piston chamber 49. Fluid pressure thereby builds up on the adjusting piston 47, shifting said piston upwardly which rotates the lever 50 to the normal position, shown in the drawings and hereinbefore described.

When the brake valve device is moved to emergency position, fluid under pressure is vented from the pipe 50 and valve piston chamber 89. The flow rate of passage 92 being restricted, the pressure in chamber 89 is thus suddenly reduced. The pressure of spring'90 then shifts the valve pist0n'88 to the left,A thus opening an unrestrictedY connection from the adjusting piston chamber 49. throughpassage 93 and passage 94 to the atmosphere. The pressure in piston chamber 49 'is thereby suddenly reduced, permitting the adjusting piston to operate the lever 53 in the same manner as hereinbefore described. Since only the valve piston chamber 89 and pipe 50 are vented by way of the brake valve device and the piston chamber 49 is suddenly vented upon operation ofthe valve piston 88, the operation of the emergency adjusting piston 47 takes place almost immediately tien with mechanism operative to limit thev braking power on a car in-a service application of the brakes, including means operative to adjust said mechanism in accordance with the load on the car, of means operative independently o the load on the car to adjust lsaid lmechanism for increasing ythe braking power in an emergency application of the brakes.

In a load brake apparatus, the combination with mechanism operative to limit the braking power on a car in a service application of the brakes, including means operative to adj ust said mechanismin accordance with the load on the car, of means operative independently of the load on the car to adjust said mechanism for increasing the brakingk power in van emergency application 'of the rakes a predetermined amount.

3.' In a load br'ake'apparatus, the combina-- tion ywith mechanism operativeto limit thev braking power on a car in a service application of the brakes, including means operative to adjust said mechanism in accordance with the load on the car, of resilient means cooperating with said mechanism and operating independently ofthe load on the car for in.-

n creasing the braking power in an emergency application ci the brakes, and fluid pressure means for normally rendering said resilient means ineffective to increase the braking power.

said mechanism to increase the braking power limitof said mechanism, and means for ren.-

dering said spring ineiec-tive to increase the braking power. l

5.' ln a load brake apparatus, the combination ywithf'mechanism operative to limit the Y braking power on Va car in a service application of the brakes, including'uid pressure means for adj ustingl said mechanism according to the load on the car, of additional iiuid pressure means operative to increase'the ady justm'ent on said mechanism a predetermined amount in an emergency application of the brakes.

6. ln aload brake apparatus, the combinay .operative yin a service application of the i ya spring for urging said abutment against kbetween said anchor member and lever for tion with mechanism operative. to limit vthe braking power on a car in a service applcation of the brakes, including meansoperative to adjust said mechanism in accordance with the load on the car, of a lever operative- 70 lyy connected to said mechanism, a spring actj ing through saidlever to increase the braking y v power limit of said mechanism, and means brakes to render said springinedective.

'i'. In a load brake apparatus, the combination with mechanism operative to limit the braking power on'v a car in a service applicationjof thebrakes, including means operative I to adjust said mechanism in accordance with f the load on the car, .of4 a lever operatively connected lto saidk mechanism, a spring acting through said lever to increase the braking power liinity of saidmechanism, and means lfory adjusting the pressure of said spring.`

8. In a fluid pressure brake system, `the combination with a brake valve device and a brake cylinder, of a valve operative to supply iuid under pressure to said brake cylinn der to effect an application of the brakes upon the operation `ot said brake valve device, means for controlling the'operation of said valve, saidnieans comprising aidiaphragm, an abutment engaging said diaphragm, ,and L9 f 5 said diaphragm, means for adjusting the pressure of said spring according to the load on the car, alever adapted to engage said abut-l ment, an anchor member, a spring interposed operating said lever `to increase the pressure on said diaphragm a predetermined degree, means orvarying the force of said spring, a piston normally subject to fluid under pressure for rendering said lever inoperative and subject to atmospheric pressure when said Y brake valve device is in emergency position or'rendering'said lever operative.

9'. In a load brake apparatus, the combina- 4 tion with a brake cylinder, of a valve for-11(I supplying duid under pressure to said brake cylinder, means for controlling the operation of said valve, said means comprisingv a diaphragm subject to pressure in the brake cylinder, an abutment engaging "said diaphragm, and a spring operative on said abutment with a pressure according tothe load on acar, a .lever operatively mountedon the casing of said means,"one end of said lever being adapted to engage said abutment, anY

anchor member, a spring interposed between said lever and anchor member for "causing said lever toengage said abutment'to increase the pressure on said diaphragm in an emerg-rency application of the brakes,arod opera-l tively connected toxsaid lever :and a piston adaptedrto be moved into and outof engagement with said rod `forrendering said lever effective and ineffective; j E;

j l0. In' aload brake apparatus, the ,combi-"i130 nation with means operative to vary the braklng power 1n accordance with the load ons. car 1n effecting a service application of the brakes, and means operative in effecting rlo an emergency application of the brakes for causing-the first mentioned means to increase the braking power a predetermined amount overthat obtained in a service application of the brakes.

11. In a load brake apparatus, the combination with means operative to vary the braking power in accordance with the load on a.v car in effecting a. service application of the brakes, and lever ymeans operative in effecting an emergency application of the brakes for increasing the braking power a predetermined amount over that obtained in a service application of the brakes and operative upon the release of the brakes after an emergency application to be ineffective in a succeeding service application of the brakes. '12. Ina load brake apparatus, the comb1- y nation with a valve for supplying fluid under pressure to the brake cylinder', of pressure sensitive means for controlling the operation of said valve, pressure means operative at one time to control the operation of said pressure sensitive means and other pressure means operative ywith the first mentioned pressure' means at another time to control the operation of said pressure sensitive means.

' 13. In a fiuid pressure brake, the combination with a brake cylinder, of' a valve for controlling the supply of fiuid under pressure to the brake cylinder, a spring, a movable abutment subject to the opposing pressures of the brake cylinder and said spring for operating said valve, an additional spring, and means operative upon effecting an emergency application of the brakes for subjecting said abutment to the pressure of said additional spring.

14. In a Huid pressure brake, the combination with a brake cylinder, of a valve for controlling the supply of fluid under pressure to the brake cylinder, a spring, a movable abutment subject to the opposing pressures of the brake cylinder and said spring for operating said valve, an additionalspring, a brake valve device, and means operative in one position of said brake valve device for subjecting said abutment to the pressure of said additional spring.

15. In a fiud pressure brake, the combination with a brake cylinder, of a valveV for controlling the supply of fluid under pressure to the brake cylinder, a spring, a movable vabutment subject to the opposing pressures device for controlling the fluid pressure on said fluid pressure operated means.

f In testimony whereof I have hereunto set my hand, this 18th day of February, 1929. MILTON L. HANCOCK. 

